Pediatric thyroid

Question 1

congenital hypothyroidism

Answer 1

Hspanics>Whites>Blacks
Absent thyroid or small ectopic thyroid (dysgenesis 75%-85%), 2% familial

Dyshormonogenesis (10%)

Iodine deficiency

Central hypothyroidism (5% or less, usually MPHD)
Transient late maturation, Abs from mom, goitrogens, Drugs

Question 2

Presentation of congenital hypothyroidism

Answer 2

Most infants are asymptomatic at birth (hence the need to screen), if untreated: lethargy, slow movement, hoarse cry, feeding problems, constipation, macroglossia, umbilical hernia, large fontanels, hypotonia, dry skin, hypothermia, and prolonged jaundice

Question 3

Newborn Screening

Answer 3

Measures T4 and/or TSH

Most states rely on high values of TSH ( can miss central hypothyroidism or delayed TSH rise)

Question 4

Treatment of congenital hypothyroidism

Answer 4

Levothyroxine (peripheral deiodination to T3)
Keep T4 or Total T4 should be kept in the upper range of normal during the 1st yr of life
Serum TSH should be kept under 5

Goal- growth and mental development that is as close as possible to their genetic potential

Inverse relationship between IQ and the age of diagnosis- compliance critical in 1st 3yrs of life since this may result in irreversible damage
Hypothyroidism after age 3 does not affect brain development

Even with treatment at 4 months–Bone age is closeish to normal, but mental age is very low